Centripetal Acceleration Part II

(From previous question) In order for a satellite to move in a stable circular orbit of radius 6689 km at a constant speed, its centripetal acceleration must be inversely proportional to the square of the radius of the orbit.

What is the speed of the satellite? The G is 6.67259e-11 and the mass of the earth is 5.98e24kg.

The answer to this was 7723.55 m/s.

Part II:

Find the time required to complete one orbit. Answer in units of h.

2. Relevant equations

The book only gives one equation for T referencing orbits, which is v=2pir/T

3. The attempt at a solution

v=2pi/T
7723.55 = 2pi/T
7723.55T = 2pi
T = 2pi/7723.55
T = .000814

I think the homework system even laughed at me when I entered that answer :)